In the hinge field it is often necessary to control the angular position of a first member which is rotatably coupled to a second member by a hinge. A common application of such a hinge is in the computer display field. Conventional pivotable computer displays are found in laptop, notebook and palmtop computers. However, such displays typically pivot with one degree of freedom between open and closed positions. In a notebook computer, for example, the hinge housing is normally structurally fastened to the base of the computer and the shaft is connected to the screen of the computer. When the screen is rotated, it is held in an angular position by the torque generated between the friction elements in the hinge and the shaft.
Desktop displays or monitors are conventionally mounted on a desk or other flat surface proximate the user. While the monitor can move with respect to its mounting base it typically is limited to rotating about a vertical axis and pivoting about a horizontal axis to adjust the screen position. If the user wishes to vertically raise the monitor it must be moved to a fixed shelf or mounted on an adjustable arm which is secured to the desk. Such adjustable arms have to have significant structural integrity due to the size and weight of the monitor. Because of the size and weight of conventional computer monitors, there has been an emphasis on developing flat panel displays for desktop computers.
Flat panel displays are small and light enough to be mounted on an adjustable arm which can allow the user to locate the display at a particular location. Once located, the display needs to be tilted and swiveled to the correct viewing angle. Tilt and swivel devices are usually mounted on the terminal end of the adjustable arm and are directly mounted to the back of the flat panel display. The center of gravity of a flat panel display is usually located proximate the front, center of the panel due to the weight of the display screen. The flat panel display is connected to its tilt and swivel mechanism at the back, center of the flat panel display. As a result, a relatively large torque moment (e.g., between 45-50 in-lb.) is generated between the horizontal axis of rotation and the center of gravity of the flat panel display, which tends to rotate the flat panel display downward, away from a set position. The existing torque moment also counteracts a lifting force, making it difficult for a user to rotate the flat panel display upward about the horizontal axis. Thus existing tilt and swivel devices must be strong enough to hold the flat panel display in the selected tilt position, counteracting the torque created by the center of gravity of the flat panel display.
Existing tilt and swivel devices do not effectively counterbalance the torque moment inherent in flat panel displays. The conventional approach has been to create a tilt mechanism which uses a significant amount of friction to hold the flat panel display in a selected tilt position. However, the friction force which is created to maintain the flat panel display in position is problematic because it acts in both directions of tilting. Thus, to tilt the flat panel display upward the fiction force and the torque moment must be overcome and to tilt the flat panel display downward only the difference between the friction force and the torque moment must be overcome. Tilting the flat panel display upwardly against the torque moment and the friction force is often difficult for the user. Thus, depending upon the direction of movement, the user encounters a different feel as the flat panel display is tilted.
Additionally, users are desiring flat panels which can swivel about a vertical axis to enable the flat panel to be turned about the vertical axis, providing the user more flexibility in the use of the flat panel. Existing tilt and swivel devices do not provide for smooth, clean motion of the display panel with respect to the terminal end of the adjustable arm. Conventional tilt and swivel devices are also relatively expensive and with today""s cost conscious computer market it is an important factor.
Hence, a need exists for a tilt and swivel device for a flat panel display which is relatively inexpensive, provides clean, smooth operation and maintains its position once it is placed in the preferred location. That is, it would be beneficial to develop a tilt and swivel device which can maintain a flat panel in the set position relative to the horizontal axis, and swivel about a vertical axis, while being cost effective due to the heavily competitive nature of the computer industry. Additionally, the hinge must be stiff enough to provide the required operational features, yet be small enough to avoid the need for an adapting plate between the hinge and the back of the panel. Further, there is a need for a tilt and swivel device which can counterbalance the torque moment of the flat panel display so that tilting movement of the flat panel display is smooth and even in both directions of movement. The present invention meets the foregoing need by providing a tilt and swivel device which is a relatively inexpensive mass producible device and which provides smooth, clean operation without backlash. In the tilt mode (i.e., pivoting about a horizontal axis) the present invention uses torque elements to achieve precise angular control and biasing elements, such as coil springs, to counteract the over center balancing of the flat panel display to allow ease of upward and downward tilting. In the swivel mode (i.e., pivoting about a vertical axis) the present invention uses, inter alia, friction between to flat surfaces of dissimilar material to control the swivel position.
In one aspect, the present invention comprises a hinge connecting a first member to a second member. The hinge includes a support rotatably connected to the first member about a first axis. The hinge also includes a first torque element having a first end including an open portion and a closed portion. The first torque element also has an elongated second end extending from the closed portion. The second end of the first torque element is fixedly connected to the support. The hinge further includes a first shaft extending from the second member and being rotatable about a second axis. The first shaft has first and second ends, with the first end of the first shaft being fixedly connected to the second member. The first shaft is located within the first end of the first torque element. The hinge also includes a first biasing element positioned between the first shaft and the support and biasing the shaft to rotate about the second axis in a first direction.
In a second aspect, the present invention is a hinge connecting a first member to a second member. The hinge comprises a connector constructed of a polymeric material secured to the first member and having a first axis. The connector has a generally flat connector surface. The hinge also includes a support constructed of a metallic material rotatably connected to the connector about the first axis. The support has a first generally flat support surface, with the connector surface being biased against the first generally flat support surface. The second member is connected to the support.
In a third aspect, the present invention is a hinge connecting a first member to a second member. The hinge comprises a connector secured to the first member and having a first axis. The hinge also includes a support constructed of a metallic material rotatably connected to the connector about the first axis, with the support having a first generally flat support surface. The hinge also includes a friction piece constructed of a polymeric material which is rotatably connected to the support about the first axis and which is rotatably fixed to the connector. The friction piece is biased against the first generally flat support surface. The second member is connected to the support.